Logging well formation



F. G. BECKMAN LOGGING WELL FORMAT ION led June 5, 1957 Patented Oct. 11, 17938 UNITED STATES PATENT OFFICE LOGGING WELL FORMATION Fred G. Beckman, Muskogee, Okla.

Application June 5, 1937, Serial No. 146,658

12 Claims.

This invention relates to new and useful improvements in logging well formations.

One object of the invention is to provide an improved method of logging well formations, whereby the formation may be accurately determined at any time after the well has been completed.

An important object of the invention is to provide an improved method whereby the well formation may be accurately logged while an underreaming operation is performed, whereby as the bottom of the well bore is enlarged by such underreaming the structure of the formation may be ascertained.

Another object of the invention is to provide an improved method for ascertaining the structure of the formation at the bottom of a well which has either been abandoned and the log'of such Well lost or otherwise unavailable, which 0 method includes an underreaming operation with means for immediately conducting the well cuttings to the surface as they leave the formation, whereby said cuttings reach the surface in the order in which they are removed from `the formation, which permit an accurate logging of the formation as the underreaming proceeds.

A further object of the invention is to provide an improved method, of the character described, which includes the introduction of a material,

30 foreign to the formation, into the bottom of the v well bore, whereby when the bore is enlarged by an underreaming operation, the cuttings cannot fall to the bottom of the bore, but are immediately carried to the surface by a circulating fluid, which fiuid may circulate downwardly through the drill pipe and upwardly through the well casing in the usual manner or it may circulate reversely; that is, downwardly through the casing and upwardly through the tubing.

A construction designed to carry out the invention will be hereinafter described, together with other features of the invention.

The invention will be more readily understood 45' from a reading of the following specification and by reference to the accompanying drawing, in which an example of the invention is shown, and wherein:

.Figure 1 is a schematic sectional view of a well 50 bore having casing therein,

Figure 2 is a. similar view, showing a material foreign to the formation in the bottom of the well bore in accordance with the invention, an underreamer being shown within the well casing,

Figure 3 is a similar view, showing the under- (Cl. Z55-24) reamer cutting the formation to enlarge the well bore, and

Figure 4 is a similar view, with the method complete.

It is well known that when an oil well is first 5 drilled, a log is made of the formation of the well during the drilling operation to ascertain the structure of the formation. This is done by examining the cuttings as they reach the surface of the well, such cuttings being carried upwardly from the bottom of the well bore by a vcirculating fluid. During the initial drilling of a well, it is evident that the cuttingsmust come to the surface immediately upon their removal from the formation because obviously, they cannot fall downwardly because the ground below the drill bit is unbroken. However, after the well has been drilled and the casing set therein, it is not possible to again obtain a log of the formation through which the drill bit has passed. This formation which is below the bottom of the well casing is known as the producing area. The only` way to obtain additional cuttings from this producing formation is by means of an underreaming operation and since the underreaming begins at the bottom of the casing and proceeds downwardly toward the bottom of the hole, it will be obvious that the cuttings will fall downwardly to the bottom of the well bore as the underreaming operation continues. Therefore, it is not possible to lift or raise the cuttings with a circulating uid immediately as they are removed from the formation during the underreaming operation. For this reason, the cuttings are not carried tothe surface of the well in the order in which they are 3;

removedand an accurate log of the formation cannot be taken during the usual underreaming of the well bore.

There are many wells in the oil ilelds which have been drilled and after producing for some time are abandoned for one reason or another. There are other wells in which the producing area or the formation below the bottom of the casing becomes contaminated with mud or parain, in which case it is necessary to enlarge the well bore so as to remove this contaminated surface of said bore. There are still other wells in which a log was made at the time they were originally drilled, but the record of the formation structure has become lost or is otherwise unavailable. The advantages of being able to obtain a log of the formation of these various wells at any time after they have been drilled, are obvious.

Referring specifically to Figure 1 of the drawing, the numeral l0 designates a well bore having 55 a well casing II set therein. The lower end of the casing is anchored within the well bore by cement I2, or in any other suitable manner. The portion I of the well bore which is below the lower end of the casing II is known as the producing area and its particular structure is, of course, dependent upon the'particular field in which the well has been drilled. This portion I0' of the bore I0, which is below the lower end of the well casing, has been illustrated as consisting of four layers or strata. The uppermost layer A is a rock formation, the layer B is limestone, the layer C may be shale, while the lowermost layer or stratum D is the producing sand. When the well I0 was first drilled, a log of said well may have been taken as the drilling operation was performed but after some time, the log may have been misplaced or is otherwise unavailable. Therefore, the operator is at a loss to know just what the structure of the formation below the casing II may be.

In order to obtain another log of the formation so as to accurately ascertain the structure thereof, a material such as gravel, thick mud or some other substance which is foreign to the material of which the formation is composed, is placed in the lower end of the well bore so as to completely fill the same. A sufficient amount of this gravel E is introduced into the well bore so as to extend from the bottom thereof into the lower end of the casing, as is clearly shown in Figure 2. After this is done, an underreamer I3, which may be of any suitable construction, is lowered through the well casing I I on a drill pipe I4. The upper end of the drill pipe extends through the usual casing head I mounted on the upper end of the casing and said head is provided with suitable outlets I6. When the blades I3 of the underreamer I3 strike the upper end of the extraneous material E, a circulation is set up between the drill pipe I4 and the casing I I. This circulation is established by pumping oil, water, mud or a mixture of fluid and gas or air downwardly through the well casing II outside of the drill pipe I4. This liquid upon reaching the lower end of the casing will be forced upwardly through the usual ports (not shown) in the underreamer I3 and then upwardly through the drill pipe I4. This circulation is maintained throughout the underreaming operation. It is pointed out that although it is preferable to circulate fluid from the well casing II upwardly through the drill pipe I4, it would be possible to force the fluid or liquid downwardly through the drill pipe I4 and upwardly in the casing which would be in a reverse direction. It is pointed out that this latter method of circulation is conventional in oil field practice.

As soon as the circulation is set up, the blades of the underreamer engage the extraneous material E within the bottom of the bore I0 and rotation is imparted to the drill stem or pipe I4, whereby the underreamer is also rotated. The blades I3' cut into the material E and upon passing from the lower end of the well casing are expanded so as to also cut into the formation, as is clearly shown in Figure 3. Since the bore II) is completely filled by the material E, it will be obvious that the cuttings which are removed by the blades I3' from the wall of the formation cannot fall downwardly in the bore. Therefore, the fluid or liquid which is circulating from the casing upwardly through the drill pipe carries these cuttings upwardly through said pipe. The

removal of the cuttings occurs immediately upon the removal thereof from the formation and therefore by examining the cuttings at the surface of the well, it is possible to tell exactly what material the cutters I3 are passing through. Since the material E is extraneous to any of the material which goes to make up the formation, this material is readily identified at the surface and the remaining cuttings are those of the formation. So long as the blades I3 are rotating within the layer of rock A, the rock cuttings are being carried to the surface through the drill pipe I4. As soon as the blades enter the second layer-B, the cuttings from this layer begin to be visible at the surface. It is noted that as soon as the blades complete their travel through the first layer A, all of the cuttings which have been removed by such travel have been carried to the surface. Manifestly, as the underreamer I3 moves downwardly through the various layers of the formation, an observer at the surface of the well can accurately log the formation structure. When the underreamer reaches the bottom of the hole or bore I0, all of the extraneous material E which has been introduced thereinto will have been raised to the surface by the circulating liquid or fiuid. Therefore, when no further cuttings of the -extraneous material E are carried to the surface, the operator knows definitely that the bottom of the bore has been reached.

With the above method, it is possible to accurately ascertain the exact structure of a particular formation by merely performing an underreaming operation. It is noted that the material E which is introduced into the bottom of the bore I0 will vary, as this material must be foreign to the material of which the formation is composed so that the operator may readily recognize the cuttings from the formation proper. By calculating the distance which the underreamer has travelled while certain types of cuttings are emitting at the surface of the well. it is possible toA definitely fix the depth of any layer or stratum in the formation.

What I claim and desire to secure by Letters Patent is:

1. The method of logging the formation of drilled wells which consists in, filling the bore of the well with material capable of being removed by drilling therethrough, then drilling to enlarge the bore of the well and to remove the material, and carrying the cuttings to the surface as soon as they are removed by the drilling operation.

2. The method of logging the formation of drilled wells which consists in, filling the bore of the well with material capable of being removed by drilling therethrough, then drilling to enlarge the bore of the well and to remove the material, andcirculating'a drilling fluid through the well bore to carry the cuttings to the surface as 'soon as they are removed by the drilling operation.

3. The method of logging the formation of drilled wells which consists in, filling the bore of the well with material which is foreign to the material of which the vformation is composed, then drilling through the material to` enlarge the bore of the-well and to remove the material, and carrying the cuttings to the surface as soon as they are removed by the drilling operation.

4. The method of logging the formation of drilled wells which consists in, filling the lower end of the bore with a material which is foreign to the material of which the formation is composed, enlarging that portion of the well bore wherein such foreign material is located by drilling through the material, and carrying the cutting's to the surface as they are removed from the formation, whereby said cuttings may be examined to denote the structure of the formation which is being drilled.

5. The method of logging the formation of drilled wells which consists in, filling the lower end of the bore with a material which' is foreign to the material of which the formation is composed,lenlarging that portion of the well bore wherein such foreign material is located by drill- .ing through said material, and circulating a drilling uid through the well bore to carry the cuttings to the surface as they are removed from the formation, whereby said cuttings may be examined to denote the structure of the formation being drilled.

6. The method of logging the formation of a well having a casing set therein which consists in, filling the well bore below the casing with material, then underreaming the bore to enlarge the bore and to remove said material, the material preventing said cuttings from falling to the bottom of the bore, and carrying the cuttings to the surface as soon as they are removed by the underreaming operation.

7. The method of logging the formation of a well having a casing set therein which consists in, filling the well bore below the casing with material, then underreaming the bore to enlarge the same and to remove said material, the material preventing the cuttings from falling to the bottom of the bore, and circulating a drilling fluid through the Well bore to carry the cuttings to the surface as soon as-they are removed by the underreaming operation.

8. The method of logging the formation of a well having a casing set therein which consists in, filling the well bore below the casing with material, lowering an underreaming tool through the casing on a drill pipe, rotating the pipe and tool to enlarge the bore and remove the material, and circulating a drilling fluid through the casing and drill pipe to carry the cuttings to the surface as they are removed by the underreaming operation.

9. The method of logging the formation of a wellr having a casing set therein which consists in, filling the well bore below the casing with material, lowering an underreaming tool through the casing on a drill pipe, rotating the pipe and tool to enlarge the bore and'remove the material, and pumping a drilling fluid downwardly through the casing and upwardly through the drill pipe, whereby the cuttings are carried to the surface through said drill pipe as they are removed by the underreaming operation.

10. The method of logging the formation of a well having a casing set therein which consists in, filling the well bore below the casing with material which is foreign to the material of which the well formation is composed, lowering an underreaming tool through the casing on a drill pipe, rotating the pipe and tool to enlarge the bore and remove the foreign material, and circulating a drilling fluid through the casing and drill pipe to carry the cuttings to the surface as they are removed by the underreaming operation.

11. The method of logging the formation of a well having a casing set therein which consists in, filling the well bore below the casing with material which is foreign to the material of which the well formation is composed, lowering an underreaming tool through the casing on a drill pipe, rotating the pipe and tool to enlarge the bore and remove the foreign material, and pumping a drilling uid downwardly through the casing and upwardly through the drill pipe, whereby the cuttings are carried to the surface through said drill pipe as they are removed by the underreaming operation.

12. The method of logging the formation of a well bore which consists in filling the bore of the Well with a relatively soft material which is foreign to the material of which the formation is composed, then enlarging the well bore by drilling through the material and the formation, and carrying the removed material and formation cuttings to the surface as they are removed by the drilling operation.

' FRED G. BECKMAN. 

